In the copper processing and electrical manufacturing industries, TU0, TU1, and TU2 are three very common oxygen free bronze plate numbers. They belong to the oxygen free copper family, but due to different purities, there are significant differences in performance, usage, and price. Understanding the differences between these three is crucial for selecting the right materials.

1、 What is oxygen free copper?

Oxygen free copper refers to pure copper with extremely low oxygen content, typically below 0.002%. Compared with ordinary pure copper, oxygen free copper has higher conductivity, better processing performance, and stronger resistance to hydrogen embrittlement. It is precisely these advantages that make oxygen free copper widely used in high demand fields such as electronics, communication, and vacuum devices. TU0, TU1, and TU2 are the three main grades of oxygen free copper subdivided by purity, with lower numbers indicating higher purity.

2、 Specific indicators and characteristics of three grades

TU0: This is currently one of the highest purity oxygen free bronze medals on the market. Its copper content (including silver) is not less than 99.99%, while its oxygen content is strictly controlled within 0.0003%, which is three parts per million. Such high purity brings ultimate conductivity and thermal conductivity, while also making the material less prone to defects during deep processing. TU0 is mainly used in fields that are extremely sensitive to impurities, such as high-end electronic components, vacuum tubes, superconducting substrate materials, and conductive parts in precision instruments. Due to the complex production process, the price of TU0 is also the highest among the three.

TU1: This is a high-purity oxygen free copper with a copper content of not less than 99.97% and an oxygen content of not more than 0.001% (parts per million). The most prominent feature of TU1 is its ability to completely avoid "hydrogen sickness". The so-called "hydrogen disease" refers to the diffusion of hydrogen into copper when heated in a high-temperature reducing atmosphere containing hydrogen, which reacts with cuprous oxide in copper to generate water vapor, resulting in cracks inside the material and seriously damaging its mechanical properties and airtightness. Due to its extremely low oxygen content, there is almost no cuprous oxide present in TU1, so hydrogen sickness does not occur. This makes TU1 an ideal material for electric vacuum devices (such as traveling wave tubes, magnetrons), high-performance communication cables, electronic tube bases, vacuum switch tubes, and other products. TU1 has excellent comprehensive performance and is the most widely used high-purity oxygen free copper.

TU2: This is standard grade oxygen free copper with a copper content of not less than 99.95% and an oxygen content of not more than 0.002% (20 parts per million). Although the purity is slightly lower than TU1, TU2 still has excellent conductivity and thermal conductivity, and has a high cost-effectiveness. It also has good resistance to hydrogen embrittlement, but its tolerance limit to hydrogen disease is slightly lower than TU1. TU2 is widely used in applications that require cost but oxygen free copper performance, such as motor coils, transformer windings, busbars, electrical contacts, lead frames, and general electronic components. In terms of industrial usage, TU2 is often the largest.

3、 How to choose?

The choice of oxygen free copper mainly depends on three factors: conductivity requirements, processing environment, and cost budget.

If the product needs to withstand extremely harsh electrical or thermal conditions, or has almost zero tolerance for impurities, such as for use in precision instruments or superconducting systems, then TU0 is the only choice.

If the product needs to work in a high-temperature hydrogen containing environment, or requires extremely high airtightness and reliability, such as vacuum electronic devices, aerospace cables, then TU1 is the safest choice. It can meet performance requirements and its price is much more reasonable than TU0.

If the product is only for general electrical use, there is no special risk of hydrogen embrittlement in the working environment, and cost control is desired, then TU2 is sufficient. It can fully meet the needs of most conventional electrical equipment and has the highest cost-effectiveness.

4. Summary

TU0, TU1, and TU2 are essentially three purity levels of oxygen free copper: the smaller the number, the purer the copper, the lower the oxygen content, the better the performance, and the more expensive the price. To summarize in one sentence: TU0 is top-quality, TU1 is premium, and TU2 is excellent. In actual material selection, there is no need to blindly pursue high purity. Only by balancing specific usage requirements and economy can the best effect be achieved.